Lewis rats and non-human primates, immunized at a site distant to the eye with the retinal soluble antigen (S-antigen) in complete Freund's adjuvant, develop experimental autoimmune uveitis (EAU). Lymph node cells and peripheral lymphocytes from immunized animals manifested significant cellular immune responses measured by the lymphocyte culturing technique. Cyclosporine, a drug with specific anti-T-cell activity, has been found to be exceptionally effective in protecting rats with EAU, and suppressor cells potentially play a role in this protective mechanism.